Study Aims and Results: There is little guidance for patients and medical providers to understand how to treat people who have relapsed on a previous course of direct-acting antiviral treatment. The phase 2 study looked at two approaches to understand the best way to treat people with hepatitis C who are in need of re-treatment. Both treatment arms included MK-3682, grazoprevir/ruzasvir—once-a-day with and without ribavirin. Treatment duration was 16 weeks with ribavirin (arm a) or 24 weeks without ribavirin (arm b).

There was a high percentage of resistant-associated substitutions (RASs)—formally named resistant-associated variants (RAVs).

Conclusions: The cure rates were as follows:

16 week treatment period with ribavirin –

98% (43 of 44 pts)

24 week treatment period without ribavirin –

100% (49 of 49 pts)

Note: one patient withdrew from the study.

There were no treatment discontinuations. The most common side effects were fatigue, pruritus, rash and decreased red blood cell count (hemoglobin) in the ribavirin arm.

Editorial Comments: The study included patients with difficult re-treatment characteristics—compensated cirrhosis, genotype 1a, and single and multiple RASs. It produced good if not almost near perfect cure rates. I will be interested to see this combination in larger phase 3 clinical trials.